code: def backward(ctx, grad):
      shape = ctx.shape
      return _NewEmptyTensorOp.apply(grad, shape), None
  
file_path: gluon-cv/gluoncv/torch/data/structures/keypoints.py
imports: from typing import Any, List, Tuple, Union
  import numpy
  import torch
label_desc: Use image node_id 2 for calling the _NewEmptyTensorOp obj's underlying member method code with example usage: obj.backward(ctx, grad) and returns: _NewEmptyTensorOp,  None